fix error check, so that Random.seed actually uses OS randomness (closes #29085)

Misc/NEWS

@@ -40,6 +40,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #29085: Allow random.Random.seed() to use high quality OS randomness
+  rather than the pid and time.
+
 - Issue #29079: Prevent infinite loop in pathlib.resolve() on Windows
 
 - Issue #13051: Fixed recursion errors in large or resized

Modules/_randommodule.c

@@ -245,7 +245,7 @@ random_seed(RandomObject *self, PyObject *args)
         return NULL;
 
      if (arg == NULL || arg == Py_None) {
-        if (random_seed_urandom(self) >= 0) {
+        if (random_seed_urandom(self) < 0) {
             PyErr_Clear();
 
             /* Reading system entropy failed, fall back on the worst entropy: